The only promise that can be made about Frank Coraci’s “Blended” is that, eventually, the film does move its action to Africa, where at least there are interesting animals and beautiful scenery to enjoy. (At least, until a pair of rhinos start humping each other in plain view of a swanky hotel breakfast, if only because they just so happen to have the misfortune of being cast in an Adam Sandler film).

“Blended” spends the absolutely numbing majority of its first act stationed in the safe suburban confines of New Jersey, and there’s such little forward motion and narrative energy to the first third of the tale of single parents Jim (Adam Sandler) and Lauren (Drew Barrymore) meeting ugly that it simply seems like it will never end, or that we’ll never actually get to Africa, where some things sort of happen and everyone looks to be very much enjoying their paid vacation. That’s another “Blended” promise: eventually, it does end. It’s pretty rough going, however.

The film opens in a Hooters, as widower Jim and divorcee Lauren stumble their way through a remarkably awkward first date. The date doesn’t go well – of course not! – but neither Barrymore nor Sandler comes out looking good. At best, they seem like people not yet ready to jump into the dating pool. At worst, they appear to be feeble-minded idiots who shouldn’t be let out of the house under any circumstances, especially romantic. People don’t act like these two do, at least, not the kind of people anyone would ever want to watch fall in love on the big screen over the course of two hours, so, yes, things start out without much promise.

Through a series of dizzying contrivances (something about a nonrefundable travel package, as purchased by Jim’s boss who also happens to be dating Lauren’s best friend, who in turn balks at going on a big African trip when she discovers her paramour has kids and they’ll be there, too), Jim and Lauren and their respective children end up on vacation together in a stunning, totally Disneyfied African resort for an entire week. No one seems to totally understand that the pair is not together and that the resort’s special weeklong getaway for “blended” families doesn’t really apply to them, but it doesn’t quite matter, because eventually, it will all apply.

They will blend, and when they blend, Terry Crews and a large group of singing resort employees (Crews’ crew, perhaps?) will pop up to sing about it, because this is a thing that happens at least five times throughout the film. Sound nonsensical? It is.

There is something to be said for the basic plotline of “Blended” and the idea of blending in general, and it’s certainly a pleasingly mature idea for a film that falls into the generally fizzy romantic comedy genre. Yet the final film is treated as being just another Adam Sandler film, just another excuse for offensive jokes and off-color sight gags, just another reason for using lowest common denominator humor to tell a tale. It wears on its viewership, really, and it’s just not funny.

Jim and Lauren’s kids have actual issues they need to work through – one of Lauren’s sons has some problems with anger she should probably address, while Jim’s middle child consistently holds on to a delusion that her dead mother is alive – and while it’s admirable that such problems are presented in an otherwise light-hearted film, they’re consistently played for laughs, not real heart. Despite the often goofy and gross nature of the film, the parenting problems that both Lauren and Jim face are very real – Jim’s inability to raise his daughters as anything other than tomboys, because that’s all he knows, is particularly on-point – but even when the film goes for emotion, the attempt is confusing and the effect is bothersome. The off-handed nature in which both parents treat their obviously pained and troubled children is also just plain problematic, and plenty of “Blended” could easily be used as fodder for some guide on how not to raise your children.

Both Barrymore and Sandler are working with some pretty common tropes here, and at least Colaci, along with a script by Ivan Menchell and Clare Sera, telegraph that early on. Sandler plays the guy he always plays, the lovable goof with bad manners but a secret heart of gold. If you loved Sandler in his other team-ups with Barrymore, “The Wedding Singer” and “50 First Dates,” you’ll love him here. Really.

Barrymore doesn’t fare quite as well, oddly enough. Lauren is an organizer by nature – and by trade, she runs a closet organizing service with her best friend – and she’s portrayed early on as an uptight weirdo who really needs to loosen up (Joel McHale, playing her skeevy ex-husband, never misses an opportunity to drive that point home). Barrymore’s performance is oddly stilted throughout the first half of the film – perhaps she’s just uncomfortable being saddled with the kind of cliché-ridden role she should have long since graduated from? – but she does eventually ease into the part, just as Lauren starts to ease into both Africa and Jim.

The film does also boast some solid supporting talent, especially Kevin Nealon as a fellow guest at the African resort who initially seems to be just another old hornball with a new wife who eventually reveals a real knack for live, in-person, highly obvious narration. The various kids in the film – Lauren’s two boys and Jim’s three girls – are also charming, and Bella Thorne, as Jim’s oldest Hilary, is a real standout. Shaq is also there, because there was apparently some kind of cameo quota that had to be met before the film could complete production.

If nothing else, you may want to go to Africa after seeing “Blended,” but only because getting far away from every single multiplex playing the film sounds like a good idea.